9 entries under brainteaser topic. ×

27
enigma(noun, trouble, challenge, question, secret)
21
mystery(noun, trouble, difficulty, challenge, question)
19
riddle(noun, trouble, challenge, question, secret)
18
conundrum(noun, trouble, challenge, question, secret)
14
secret(noun, trouble, challenge, question, puzzle)
6
mystification(noun, trouble, challenge, question, secret)
6
puzzlement(noun, trouble, challenge, question, secret)
4
puzzle(noun, trouble, challenge, question, secret)
1
head-scratcher(noun, trouble, challenge)
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APASmart Define. (2016). closed book thesaurus. Retrieved September 24, 2026, from https://smartdefine.org/closed_book/thesaurus/synonyms
ChicagoSmart Define. 2016. "closed book thesaurus" https://smartdefine.org/closed_book/thesaurus/synonyms (accessed September 24, 2026).
HarvardSmart Define 2016, closed book thesaurus, Smart Define, viewed 24 September, 2026, <https://smartdefine.org/closed_book/thesaurus/synonyms>.
MLASmart Define. "closed book thesaurus" 31 March 2016. Web. 24 September 2026. <https://smartdefine.org/closed_book/thesaurus/synonyms>